package Wuli_2023;

/**
 * 圆
 */
public class circle extends geometry_2D{
    double r;  //半径

    circle(double r) {
        this.r = r;
    }
    @Override
    double getS() {
        return Math.PI*r*r;
    }

    @Override
    double getC() {
        return 2*Math.PI*r;
    }

}
